:root {
  --blue: #007aff;
  --blue-dark: #0051d5;
  --gray-1: #1d1d1f;
  --gray-2: #86868b;
  --gray-3: #d2d2d7;
  --gray-bg: #f5f5f7;
  --white: #ffffff;
}

* { box-sizing: border-box; }

html {
  -webkit-text-size-adjust: 100%;
  scroll-behavior: smooth;
}

body {
  font-family: -apple-system, BlinkMacSystemFont, "SF Pro Text", "SF Pro Display",
               "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
  font-size: 17px;
  line-height: 1.6;
  color: var(--gray-1);
  background: var(--gray-bg);
  margin: 0;
  padding: 0;
  -webkit-font-smoothing: antialiased;
}

.container {
  max-width: 720px;
  margin: 0 auto;
  padding: 48px 24px 80px;
}

/* ===== 首页专用 ===== */
.hero {
  text-align: center;
  padding: 60px 20px 30px;
}

.hero h1 {
  font-size: 48px;
  font-weight: 700;
  letter-spacing: -0.02em;
  margin: 0 0 12px;
  color: #000;
}

.hero .subtitle {
  font-size: 20px;
  color: var(--gray-2);
  font-weight: 400;
  margin-bottom: 48px;
}

.platform-cards {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 16px;
  max-width: 600px;
  margin: 0 auto 32px;
}

.platform-card {
  background: var(--white);
  border-radius: 16px;
  padding: 36px 24px;
  text-align: center;
  text-decoration: none;
  color: var(--gray-1);
  transition: transform 0.15s ease, box-shadow 0.15s ease;
  border: 1px solid var(--gray-3);
  display: block;
}

.platform-card:hover {
  transform: translateY(-2px);
  box-shadow: 0 8px 24px rgba(0, 0, 0, 0.08);
  border-color: var(--blue);
}

.platform-card .icon {
  font-size: 48px;
  margin-bottom: 12px;
  display: block;
}

.platform-card .name {
  font-size: 22px;
  font-weight: 600;
  color: var(--blue);
  margin-bottom: 4px;
}

.platform-card .hint {
  font-size: 14px;
  color: var(--gray-2);
}

.intro-text {
  max-width: 600px;
  margin: 24px auto 0;
  font-size: 15px;
  line-height: 1.7;
  color: var(--gray-2);
  text-align: center;
}

/* ===== 教程页专用 ===== */
.page-header {
  padding-bottom: 24px;
  margin-bottom: 32px;
  border-bottom: 1px solid var(--gray-3);
}

.page-header .kicker {
  color: var(--blue);
  font-size: 14px;
  font-weight: 600;
  letter-spacing: 0.02em;
  margin: 0 0 8px;
  text-transform: uppercase;
}

.page-header h1 {
  font-size: 36px;
  font-weight: 700;
  letter-spacing: -0.01em;
  margin: 0 0 12px;
  color: #000;
}

.page-header .lead {
  font-size: 17px;
  color: var(--gray-2);
  margin: 0;
}

/* 步骤编号 */
h2 {
  font-size: 24px;
  font-weight: 600;
  margin: 48px 0 16px;
  color: #000;
  display: flex;
  align-items: center;
  gap: 12px;
}

h2 .step-num {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 32px;
  height: 32px;
  background: var(--blue);
  color: white;
  border-radius: 50%;
  font-size: 15px;
  font-weight: 700;
  flex-shrink: 0;
}

h3 {
  font-size: 19px;
  font-weight: 600;
  margin: 24px 0 12px;
  color: #000;
}

p { margin: 12px 0; }

strong { font-weight: 600; color: #000; }

a { color: var(--blue); text-decoration: none; }

a:hover { text-decoration: underline; }

/* 代码 */
code {
  font-family: "SF Mono", Menlo, Monaco, Consolas, monospace;
  font-size: 14.5px;
  background: var(--gray-bg);
  padding: 2px 6px;
  border-radius: 4px;
  color: #c7254e;
  border: 1px solid rgba(0,0,0,0.04);
}

pre {
  background: #1d1d1f;
  color: #f5f5f7;
  border-radius: 12px;
  padding: 18px 20px;
  overflow-x: auto;
  margin: 16px 0;
  font-size: 14px;
  line-height: 1.55;
  -webkit-overflow-scrolling: touch;
}

pre code {
  background: none;
  padding: 0;
  color: inherit;
  border: none;
  font-size: inherit;
}

/* 卡片 */
.card {
  background: var(--white);
  border-radius: 12px;
  padding: 20px 24px;
  margin: 16px 0;
  border: 1px solid var(--gray-3);
}

.card.blue {
  background: #eaf4ff;
  border-color: #b6dcff;
}

.card.yellow {
  background: #fffbe6;
  border-color: #ffe58f;
}

.card.green {
  background: #e8f7ec;
  border-color: #a8e0b2;
}

.card p:first-child { margin-top: 0; }
.card p:last-child { margin-bottom: 0; }

/* 列表 */
ul, ol {
  padding-left: 24px;
  margin: 12px 0;
}

li { margin: 6px 0; }

/* 分隔线 */
hr {
  border: none;
  border-top: 1px solid var(--gray-3);
  margin: 48px 0;
}

/* 底部导航 */
.page-footer {
  margin-top: 64px;
  padding-top: 32px;
  border-top: 1px solid var(--gray-3);
  display: flex;
  justify-content: space-between;
  align-items: center;
  font-size: 14px;
  color: var(--gray-2);
  flex-wrap: wrap;
  gap: 12px;
}

.page-footer a {
  display: inline-flex;
  align-items: center;
  gap: 6px;
}

/* 移动端 */
@media (max-width: 560px) {
  .container { padding: 32px 20px 60px; }
  .hero { padding: 40px 16px 20px; }
  .hero h1 { font-size: 36px; }
  .hero .subtitle { font-size: 17px; }
  .platform-cards { grid-template-columns: 1fr; }
  .page-header h1 { font-size: 28px; }
  h2 { font-size: 20px; }
  h3 { font-size: 17px; }
  pre { font-size: 13px; padding: 14px 16px; }
  body { font-size: 16px; }
}